Hi and welcome to JustAnswer,Thank you for the question and your patience. Should you still need assistance for information purposes only...Initially, what seems to be wrong with the power? ...completely/electrically dead?
Have you tried another power source/outlet?
And if internal repairs needed, are you then considering a DIY (do-it-yourself) repair approach? If yes, do you have access to and familiar with a multi-meter and even perhaps a soldering iron?
Perhaps more importantly, would you be comfortable working on the inside circuitry? ...LIVE!
Great on the DIY!
And bear with us; re-confirm and post back with the complete model number of the "... jbl eon..."
Carefully open up the JBL and then post back with clear closeup pictures of the power supply board. Click HERE. This would allow common reference for the test points.